1. Field of the Invention
The present invention relates to a connection element for a bolt and including a member for receiving the bolt and having a bore through which the bolt extends, and a spring located in the bore and formlockingly cooperating with the outer profile of the bolt for locking the same.
2. Description of the Prior Art
The connection elements of the type described above are designed for fixedly retaining a bolt in place. A known connection element includes a receiving member with thread elements extending radially to a bolt and biased in a setting direction. Upon insertion of the bolt, the thread elements spring substantially radially outwardly, engaging in the following outer profile of the bolt. With a load acting in a direction opposite to the setting direction, the thread elements are completely pressed into the outer profile of the bolt, fixing the bolt in place.
The advantage of the above-described connection element consists in that it can be simply and economically produced. Another advantage of the above-described connection element consists in that it can be easily handled. The drawback of this solution consists in that the bolt can be loaded only in a direction opposite the setting direction. This significantly limits the use of the above-described connection element.
Another connection element is disclosed in German Publication DE-A1-198 31 001. The disclosed connection element includes a spring acting as a locking member and which formlockingly cooperates with the bolt outer profile.
The advantage of the connection element consists in that the connection element can be easily pushed over the bolt. When the connection element is pushed over the bolt, the spring expands and slides over the bolt, in particular, over the bolt outer profile. This eliminates a screw movement. Again, the drawback of the disclosed connection element consists in that the load can be applied only in one direction. The disclosed connection element does not insure a reliable connection when dynamic loads are applied to the bolt.
Accordingly, an object of the present invention is to provide a connection element for a bolt with an outer profile which can be easily and rapidly mounted.
Another object of the present invention is to provide a connection element of the above-described type which would insure a reliable connection and which is capable of withstanding loads acting in opposite axial directions with respect to the bolt axis.
These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing two, displaceable relative to each other, coaxial with each other and with the spring, cone sleeves located in the bore of the receiving member and encompassing the spring, and having each a through-bore which expands conically, at least at its end adjacent to the spring, and which has a largest inner diameter, which is larger than an outer diameter of the spring, and a smallest diameter which is smaller than the outer diameter of the spring but which is at least equal to an outer diameter of the bolt.
The arrangement of the spring between two, displaceable relative to each other, cone sleeve insures that the bolt can be fixed by displacement of one of both sleeves. The at least partially conical through-bore, which is provided at an end of the cone sleeve adjacent to a spring end, insures that upon tightening of the sleeves relative to each other in the axial direction, a pressure, which is applied to the spring as a result of relative tightening of the sleeves, causes displacement of the spring turns into the outer profile of the bolt, resulting in a formlocking connection of the spring with the bolt. Matching of the outer diameter of the spring with the dimensions of the sleeve through-bore insures that the spring, on one hand, is at least partially received in the through-bores of both sleeves at least during axial tightening of the sleeves and, on the other hand, the spring would not be completely received in the through-bores. With the cone sleeves not being tightened relative to each other, the bolt can be easily inserted into the connection element and displaced there as needed. When the bolt is being inserted, the spring expands radially and slides over the outer profile of the bolt.
Advantageously, the spring is formed as a cylindrical, one-piece wire spring having two wire ends and a plurality of turns. Thus, there is provided a spring that can be economically produced using conventional means. The cylindrical shape of the spring insures compactness of the connection element.
Essential is that both spring ends can be partially received in the respective through-bores of respective cone sleeves, whereby fixing of the bolt is insured. Instead of wire, another material, e.g., plastics, can be used.
Advantageously, each of the cone sleeves has a longitudinal slot opening toward a spring end and a longitudinal wall of which forms a stop for the spring end.
The stop limits the rotation of the spring relative to the cone sleeves. According to an advantageous embodiment of the present invention, the cone sleeves have a longitudinal slot having a width corresponding to 0.25÷0.2 of the thickness of the sleeve wall.
Advantageously, the receiving member is formed of two, axially displaceable relative to each other elements. The two cone sleeves are connected with the two elements forming the receiving member for joint displacement therewith. Thereby, the sleeves can be displaced relative to each other by the receiving member-forming elements which can be connected with each other by thread means. The two elements form stops for respective sleeves. And the sleeves can be displaced relative to each other by rotation of the two receiving member-forming elements relative to each other in opposite directions. The two, receiving member-forming elements insure a controlled displacement of the two cone sleeves.
In order to provide for adjustment of a radial width of the spring, one of the cone sleeve has an engagement portion that projects beyond the receiving member, and the other cone sleeve is connected with the receiving member without a possibility of rotation relative thereto.
The radial width of the spring is adjusted by rotation of the cone sleeve with the engagement portion relative to the receiving member. Because the other, opposite sleeve is connected with the receiving member without a possibility of rotation relative thereto and both spring ends engage the stop surfaces of the opposite sleeves, the rotation of one of the sleeve relative to another sleeve provides for a change of the spring width. The radial width of the spring determines the strength of the connection between the bolt and the connection element. Thus, by controlling the width of the spring, the strength of the connection of the bolt with the connection element can be controlled.
Advantageously, the receiving member has a bore section the diameter of which corresponds to the outer diameter of the bolt and which provides for an alignment of the bolt with the axis of the connection member. This insures proper fixation of the bolt in any arbitrary axial position of the bolt.
Advantageously, the longitudinal slot has a substantially V-shape which widens in the spring direction. This facilitates the insertion of the spring end in the through-bore of a respective cone sleeve.
To insure a high elasticity and a load-carrying capability, advantageously, both cone sleeves and the spring are formed of spring steel, in particular of a hardened spring steel.
According to a further advantageous embodiment of the present invention, the inner diameter of the spring at least corresponds to the outer diameter of the bolt. When the inner diameter of the spring corresponds to the outer diameter of the bolt, the pitch of the spring turns needs not correspond to the pitch of the outer thread of the bolt. This permits to use bolts with an arbitrary outer profile. The connection of the bolt with the connection element is insured, in this case, by tightening the cone sleeves relative to each other.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.